Slings for urinary incontinence and the application of cell-based therapy

Animal models, treatment options, and biomaterials for female stress urinary incontinence

In the quest to tackle stress urinary incontinence (SUI), the synthesis of cutting-edge biomaterials and regenerative materials has emerged as a promising frontier. Briefly, animal models like vaginal distension and bilateral ovariectomy serve as crucial platforms for unraveling the intricacies of SUI, facilitating the evaluation of innovative treatments. The spotlight, however, shines on the development and application of novel biomaterials-ranging from urethral bulking agents to nano-gel composites-which aim to bolster urethral support and foster tissue regeneration. Furthermore, the exploration of stem cell therapies, particularly those derived from adipose tissues and urine, heralds a new era of regenerative medicine, offering potential for significant improvements in urinary function. This review encapsulates the progress in biomaterials and regenerative strategies, highlighting their pivotal role in advancing the treatment of SUI, thereby opening new avenues for effective and minimally invasive solutions.

The use of autologous skeletal muscle progenitor cells for adjunctive treatment of presumptive urethral sphincter mechanism incompetence in female dogs

BACKGROUND

Urethral sphincter mechanism incompetence (USMI) is a common problem in female dogs, but some dogs fail to achieve continence with standard treatment. Urethral submucosal injection of autologous skeletal muscle progenitor cells (skMPCs) previously has been shown to restore urethral function in a canine model of USMI.

HYPOTHESIS/OBJECTIVE

To determine if urethral submucosal injection of skMPC alters continence in dogs with USMI that had previously failed standard medical management. We hypothesized that the injections would lead to improved continence.

ANIMALS

Fifteen client-owned dogs with USMI that had failed standard medical management.

METHODS

Dogs were prospectively enrolled into a single-armed clinical trial. Once enrolled, a triceps muscle of each dog was biopsied; the tissue specimens were digested, cultured, and expanded to 100 million cells before injection into the urethral submucosa using a surgical approach. Continence was assessed at baseline and 3, 6, 12, and 24 months post-injection using continence scores and urethral pressure profilometry.

RESULTS

Median continence scores increased significantly from baseline at 3, 6, 12, and 24 months. Increases were seen in 14 of 15 dogs with 7, 6 or 1 dog achieving scores of 5, 4 or 3, respectively. Additional medication was required to achieve continence in all but 2 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Urethral submucosal injection of skMPC can be used adjunctively to improve continence in dogs with difficult to manage USMI. The procedure is labor intensive but well tolerated; most dogs will require continued medication to remain continent.

Cell Technologies in the Stress Urinary Incontinence Correction

The scientific literature of recent years contains a lot of data about using multipotent stromal cells (MSCs) for urinary incontinence correction. Despite this, the ideal treatment method for urinary incontinence has not yet been created. The cell therapy results in patients and experimental animals with incontinence have shown promising results, but the procedures require further optimization, and more research is needed to focus on the clinical phase. The MSC use appears to be a feasible, safe, and effective method of treatment for patients with urinary incontinence. However, the best mode for application of cell technology is still under study. Most clinical investigations have been performed on only a few patients and during rather short follow-up periods, which, together with an incomplete knowledge of the mechanisms of MSC action, does not make it possible for their widespread implementation. The technical details regarding the MSC application remain to be identified in more rigorous preclinical and clinical trials.

Stem Cells in Clinical Trials for Pelvic Floor Disorders: a Systematic Literature Review

Pelvic floor disorders (PFDs) include a series of conditions that can be poorly tolerated, negatively affecting the quality of life. Current treatment options show unsatisfactory results and new ones are therefore needed. Stem cell (SC) therapy might be an alternative treatment strategy. This systematic review aims to define the state of art of SC therapy for PFDs in clinical trials, by systematically reviewing the available evidence. A systematic search strategy was conducted up to November 7, 2020, in PubMed, Scopus, Cochrane Library, and ISI Web of Science. Preclinical studies on animal models were not considered. Studies were included when the patients were affected by any PFDs and cells were isolated, cultured, and characterized as SC. The study protocol was registered in PROSPERO (CRD42020216551). A total of 11 prospective clinical studies were included in the final assessment, specifically 7 single-arm studies dealing with SC therapy for stress urinary incontinence and 4 with anal incontinence. Among the latter, there were two prospective, single-arm studies and two randomized controlled trials. No papers concerning the use of SC for prolapse repair were retrieved. Due to the great heterogeneity, data pooling was not possible. Stem cell injection resulted in a safe procedure, with few mild adverse side effects, mostly related to harvesting sites. However, a clear beneficial impact of SC treatment for the treatment of pelvic floor disorders could not be demonstrated. Further larger targeted studies with control arms are needed before any conclusions can be made.

A systematic review of stem cell therapy treatment for women suffering from stress urinary incontinence

BACKGROUND

Stem cell therapy (SCT) is used for regeneration of injured tissues. This seems a novel promising strategy for restoring urethral sphincter function in patients with stress urinary incontinence (SUI).

OBJECTIVE

To summarize the clinical trials available to date on SCT for treatment of SUI in women.

SEARCH STRATEGY

PubMed, Cochrane Library, Scopus and Embase.

SELECTION CRITERIA

Prospective interventional case series, randomized prospective interventional study and prospective cohort study assessing women aged 18 years and over diagnosed with SUI and treated by SCT were included. The quality of studies was finally assessed using the JBI Critical Appraisal Checklists according to the PRISMA guidelines.

DATA COLLECTION AND ANALYSIS

Nineteen studies (n = 773 patients) were selected for final analysis. These were conducted worldwide between the years 2005 and 2016. Although different cell types were used, general processing steps were similar. The follow-up period ranged between 6 weeks and 6 years and included common subjective and objective evaluation tools.

RESULTS

Overall, the studies imply that SCT for treatment of SUI is a safe and effective treatment.

CONCLUSION

In our opinion, the initial results of SCT for the treatment of SUI seem promising. Standardization and validation of this treatment modality is required before it can be recommended for routine use.

Simulated vaginal delivery causes transients vaginal smooth muscle hypersensitivity and urethral sphincter dysfunction

BACKGROUND

Although pelvic floor dysfunction (PFD) has a multifactorial etiology, pregnancy and childbirth are considered crucial events predisposing to urinary incontinence as well as pelvic organ prolapse, which are highly prevalent. Rats are the most frequently used animal model and pudendal nerve crush (PNC) and vaginal distension (VD) are often used to mimic vaginal delivery.

OBJECTIVE

To document the time course of events after simulated vaginal delivery (SVD) on the urethral sphincter and the vaginal smooth muscle layer.

MATERIALS AND METHODS

Virgin female Sprague-Dawley rats were subjected to SVD (PNC + VD) or sham surgery and evaluated at 7, 14, 21, and 42 days after the injury. Urethral function was determined in vivo by microultrasound during cystometry and vaginal smooth muscle layer was harvested for in vitro pharmacologic investigation by isometric tension recording. Furthermore, vaginal and urethral samples were investigated by immunohistochemistry and real-time quantitative polymerase chain reaction.

RESULTS

Microultrasound showed no bursting of the urethral sphincter in the SVD group at 7 days with a functional recovery starting at 14 days, and normal bursting at 21 and 42 days. Vaginal smooth muscle showed higher sensitivity to carbachol at 14 and 21 days after injury; however, at 42 days, its sensitivity decreased when compared with sham.

CONCLUSION

SVD induces urethral dysfunction and a shift in vaginal smooth muscle contractile responses to carbachol.

Cell-based therapy for the treatment of female stress urinary incontinence: an early cost-effectiveness analysis

AIM

To perform an early cost-effectiveness analysis of in vitro expanded myoblasts (IVM) and minced myofibers versus midurethral slings (MUS) for surgical treatment of female stress urinary incontinence.

METHODS

Cost-effectiveness and sensitivity analyses were performed using a decision tree comprising previously published data and expert opinions.

RESULTS & CONCLUSION

In the base case scenario, MUS was the cost-effective strategy with a negative incremental cost-effectiveness ratio compared with IVM and a positive incremental cost-effectiveness ratio compared with minced myofibers. However, the sensitivity analysis indicates that IVM may become an alternative providing greater effect at a higher cost. With the possibility of becoming more effective, IVM treatment would be advantageous over MUS given its reduced invasiveness and lower risks of complications.

Efficacy and Initial Safety Profile of CXCL12 Treatment in a Rodent Model of Urinary Sphincter Deficiency

Disappointing results of skeletal muscle precursor cell (skMPC) therapy for women with intrinsic urinary sphincter deficiency (ISD) associated urinary incontinence has increased interest in alternative sphincter regenerative approaches. This study was to measure the safety and efficacy of the cell homing chemokine CXCL12 versus skMPCs in a rat model of ISD. Thirty‐six adult female Sprague Dawley rats were divided into 6 treatment (Tx) conditions: (a) no ISD/noTx [Control]; (b) ISD/noTx; (c) ISD + skMPCs; (d) ISD + 3.5 mg CXCL12; (e) ISD + 7mg CXCL12; and (f) ISD + 14 mg CXCL12. Tx's were injected directly into the sphincter complex 30 days post ISD and rats euthanized 30 days post Tx. Blood samples for measurements of kidney and liver function, white and red blood cell counts, were taken at baseline and at euthanasia. Leak point pressures (LPP) were measured prior to, and sphincter collagen/muscle content measured after, euthanasia. There were no effects of treatments on white or red/white blood cell counts, kidney/liver function tests or histopathology of the urinary sphincter complex or surrounding tissues. ISD lowered LPP 35% and sphincter muscle content by 17% versus control rats. CXCL12, but not skMPC injections, restored both LPP to control values in a dose‐dependent fashion. Both skMPCs and CXCL12 restored sphincter muscle content to control values. This chemokine approach may represent a novel therapeutic option for ISD and appears, at least short‐term, to produce little clinical or tissue pathology. Stem Cells Translational Medicine2017;6:1740–1746

Determinates of muscle precursor cell therapy efficacy in a nonhuman primate model of intrinsic urinary sphincter deficiency

BACKGROUND

Cell therapy for intrinsic urinary sphincter deficiency (ISD) in women has been moderately effective, and improvements are needed. To improve treatment efficacy, it is important to better understand determinates of cell efficacy in the different patient cohorts. We have reported that in nonhuman primates the chronicity of ISD may affect cell efficacy, but additional factors (age, psychosocial stress, hormone status, body weight) can be associated with many disease/treatment outcomes in women - and these factors are the focus of this study.

METHODS

Adult female cynomolgus monkeys were divided into groups: (1) younger (n = 10, 5-8 years of age) versus older (n = 10, 13-18 years of age); (2) age-matched/socially subordinate (n = 15) versus socially dominant (n = 15); and (3) age-matched lower body weight (n = 6) versus higher body weight (n = 6). Autologous skeletal muscle precursor cells (skMPCs, 5 million) were injected into the urinary sphincter 6 weeks after a surgically induced ISD procedure. Resting and pudendal nerve-stimulated maximal urethral pressures (MUP) were measured before, and 3 and 6 months post-skMPC treatment and urinary sphincter muscle/collagen content within the sphincter complex was measured by quantitative histology 6 months posttreatment.

RESULTS

Efficacy of skMPCs on MUP and sphincter muscle/collagen ratios are affected by age (average 40% reduction in efficacy, p < 0.05 vs. younger NHPs), social stress (average 30% reduction in efficacy, p < 0.05 vs. socially dominant) and body weight/fasting glucose concentrations (average 35% reduction in efficacy, p < 0.05 vs. lower body weight).

CONCLUSION

Multiple factors (age, stress-induced dysmenorrhea, and body weight) affect the efficacy of cell therapy to restore structure and function in the urinary sphincter complex in NHPs with ISD. Consideration of, and alternatives for, these patient cohorts should be considered.

Local versus intravenous injections of skeletal muscle precursor cells in nonhuman primates with acute or chronic intrinsic urinary sphincter deficiency

Background

Many factors may influence the efficacy of cell therapy for intrinsic urinary sphincter deficiency (ISD), including the route of administration of the cells and the condition of the sphincter. The goal of this study was to compare local versus intravenous administration of autologous skeletal muscle precursor cells (skMPCs) when administered to nonhuman primates (NHPs) with either acute or chronic ISD.

Methods

Thirty-two adult female monkeys were divided into eight groups (n = 4/group): (1) control; (2) surgically induced ISD/no treatment; (3) acute ISD (6-week duration)/local vehicle only; (4) acute ISD/local skMPC injection; (5) acute ISD/systemic skMPC; (6) chronic ISD (6-month duration)/local vehicle; (7) chronic ISD/local skMPC; (8) chronic ISD/systemic skMPC. Maximal urethral pressures (MUP) were measured prior to ISD, prior to treatment and at 3 and 6 months following treatment. Quantitative histology was used to measure muscle/collagen content, somatic innervation, and vascularity of the sphincter complexes.

Results

In NHPs with acute ISD both systemic and local administration of skMPCs increased resting MUP values and sphincter muscle content (p < 0.05 vs. ISD/vehicle). However, the effects of systemic skMPC administration were significantly lower than those of local injection (p > 0.05). In NHPs with chronic ISD local skMPC administration had reduced (compared to NHPs with acute ISD) effects on MUP and sphincter muscle values (p < 0.05 vs. acute ISD/skMPC); systemic administration had no effect. Pudendal nerve-stimulated increases in MUP were significant only in acute ISD NHPs with local skMPC treatment (p < 0.05 vs. resting MUP). The extent of sphincter vascularization and innervation were directly related to MUP and sphincter muscle content.

Conclusions

Both the chronicity of ISD and the route of cell injection influence the efficacy of cell therapy in monkey models of ISD. This may be related to the relative ability of cells to stimulate vascularization and re-innervation in these different treatment conditions.

Regenerative Medicine Therapies for Stress Urinary Incontinence

PURPOSE

We summarize the current state of knowledge regarding cell therapy for stress urinary incontinence and introduce new approaches of using regenerative pharmacology as an adjunct or replacement for cell therapy.

MATERIALS AND METHODS

We reviewed the literature by searching PubMed®, Ovid and Biological Abstracts. The period searched was 1975 to December 2015. The inclusion terms separately or in combination were stress urinary incontinence, cell therapy, chemokine, vascularization, innervation, secretome and/or animal models. Epublished articles were not included. We did not exclude articles based on impact factor.

RESULTS

Cell therapy is currently proposed to restore functional muscle cells and aid in closure of the sphincter in women with sphincter associated incontinence. Clinical trials have included small numbers of patients and results have varied depending on the patient cohorts and the cells used. Results of preclinical studies have also varied but show a more favorable outcome. This difference was most likely explained by the fact that animal modeling is not directly translatable to the human condition. However, preclinical studies have identified an exciting new approach to regeneration of the urinary sphincter using the components of cells (secretomes) or chemokines that home reparative cells to sites of injury.

CONCLUSIONS

Cell therapy will continue to be explored. However, a regenerative pharmacological approach to the treatment of stress urinary incontinence holds the promise of bypassing the lengthy and expensive process of cell isolation and also increasing the availability of treatment in many clinical settings. This approach requires careful preclinical modeling and attention to its health benefit-to-risk ratio.

Cell versus Chemokine Therapy in a Nonhuman Primate Model of Chronic Intrinsic Urinary Sphincter Deficiency

PURPOSE

Mixed efficacy results of autologous skeletal muscle precursor cell therapy in women with chronic intrinsic urinary sphincter deficiency have increased interest in the therapeutic value of alternative regenerative medicine approaches. The goal of this study was to compare the effects of the cell homing chemokine CXCL12 (C-X-C motif chemokine 12) and skeletal muscle precursor cells on chronic urinary sphincter regeneration in chronic intrinsic urinary sphincter deficiency.

MATERIALS AND METHODS

Five million autologous skeletal muscle precursor cells or 100 ng CXCL12 were injected in the urinary sphincter complex of adult female cynomolgus monkeys with chronic (6-month history) intrinsic urinary sphincter deficiency. These treatment groups of 3 monkeys per group were compared to a group of 3 with no intrinsic urinary sphincter deficiency and no injection, and a group of 3 with intrinsic urinary sphincter deficiency plus vehicle injection. Maximal urethral pressure was measured at rest, during stimulation of the urinary sphincter pudendal nerves at baseline and again 6 months after treatment. The monkeys were then necropsied. The urinary sphincters were collected for tissue analysis of muscle and collagen content, vascularization and motor endplates.

RESULTS

CXCL12 but not skeletal muscle precursor cells increased resting maximal urethral pressure in nonhuman primates with chronic intrinsic urinary sphincter deficiency compared to that in monkeys with intrinsic urinary sphincter plus vehicle injection (p >0.05). Skeletal muscle precursor cells and CXCL12 only partially restored pudendal nerve stimulated increases in maximal urethral pressure (p >0.05), sphincter vascularization and motor endplate expression in monkeys with chronic intrinsic urinary sphincter deficiency. Additionally, CXCL12 but not skeletal muscle precursor cell injections decreased collagen and increased the muscle content of urinary sphincter complex in monkeys with chronic intrinsic urinary sphincter deficiency compared to those with intrinsic urinary sphincter plus vehicle injection and no intrinsic urinary sphincter plus no injection (p <0.05 and >0.05, respectively).

CONCLUSIONS

These results raise questions about cell therapy for chronic intrinsic urinary sphincter deficiency and identify a chemokine treatment (CXCL12) as a potential alternative treatment of chronic intrinsic urinary sphincter deficiency.